Using Estimation to Check Answers

Using Estimation to Check Answers

Introduction

Estimation provides an approximate answer that can be used to judge whether a reported result is reasonable before completing an exact calculation.

Theory

You are helping your school librarian record a new shipment of books, and you accidentally read the stock slip as showing 840 books.

That looks far too high, so before entering it, you check whether it is reasonable.

Twenty-one boxes contain 18 books each, and one is labeled 14 books. The total is 21 times 18 plus 14.

Instead o...